whats the difference between 1.5 and 1.6 ratio rockers ??

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junior a
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whats the difference between 1.5 and 1.6 ratio rockers ??

Post by junior a » Sun Oct 04, 2009 9:57 am

i hand order new ones to fit my 155 springs,my old ones was 145 springs

rmcomprandy

Post by rmcomprandy » Sun Oct 04, 2009 10:18 am

A tenth of a ratio.
The 1.5 and 1.6 is the multiplication factor which that rocker arm has between the lifter rise and lifting the valve.

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BrazilianZ28Camaro
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Post by BrazilianZ28Camaro » Sun Oct 04, 2009 11:24 am

You can expect about 14 hp more with 1.6 Roller rockers in a average 350...

Just be careful with coil bind and piston to valve clearance.
'71 Z28 Pro-Street Camaro
Pump gas -T-ram - All motor SBC 427"
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New best 1/8 mile ET
1.45 60' / 4.12 330' / 6.38@109mph :D

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Post by bigjoe1 » Sun Oct 04, 2009 1:13 pm

That 14 HP is about the BIGGEST increase I have ever seen. If you put themon both sides, it will usually cut that down to about 7 or 8 HP, not 14


JOE SHERMAN RACING

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Post by Troy Patterson » Sun Oct 04, 2009 2:59 pm

bigjoe1 wrote:That 14 HP is about the BIGGEST increase I have ever seen. If you put themon both sides, it will usually cut that down to about 7 or 8 HP, not 14


JOE SHERMAN RACING
So, just put them on one head for best power? :lol:

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Post by BrazilianZ28Camaro » Sun Oct 04, 2009 4:06 pm

Some sources claim 16 hp from factory stamped rockers to 1.6 RR on undercammed underheaded mild 350 engines...

But I think is a bit high too :roll:

On a well developed cam/head/exaust engine increased lift and valve acceleration from bigger ratio rocker can offset any possible gain, mainly on exaust due to increased valvetrain instability and too much overlap area to the engine.

Just my $.02
'71 Z28 Pro-Street Camaro
Pump gas -T-ram - All motor SBC 427"
3308 lbs- leaf spring/Caltrac Car
29x10.5 Hoosiers
New best 1/8 mile ET
1.45 60' / 4.12 330' / 6.38@109mph :D

jeff swisher
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Post by jeff swisher » Sun Oct 04, 2009 4:12 pm

so many times i have witnessed a swap from stock rockers to 1.6 rollers and nothing changed except the thickness of your wallet

but street cars with cams in the 218-240 range at .050

you might see it at the track like 1 or 2 tenths but i have never felt it in my buttometer

never did just the 1.6 on the intake side though

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